Anti-aging plastic packaging material and preparation method thereof

Abstract

The invention relates to the technical field of plastic packaging preparation, in particular to an anti-aging plastic packaging material and a preparation method thereof.The anti-aging plastic packaging material is prepared from, by mass, 100-140 parts of polylactic acid, 60-80 parts of PBAT, 2-5 parts of a composite anti-aging agent, 1-2 parts of a lubricant, 2-4 parts of a flame retardant and 3-6 parts of a compatilizer; the composite anti-aging agent comprises a modified anti-aging agent obtained by compounding functionalized montmorillonite and modified silicon dioxide, the functionalized montmorillonite is carnosic acid grafted rare earth ion modified montmorillonite, and the modified silicon dioxide is epoxy methyl oleate grafted silicon dioxide. According to the anti-aging plastic packaging material provided by the invention, a plastic material system with multiple protection mechanisms is constructed through the synergistic effect of all the components, and the prepared plastic packaging material not only keeps good biodegradability, but also has excellent ultraviolet light resistance and oxidation resistance.

Description

Technical Field

[0001] The invention relates to the technical field of plastic packaging preparation, and in particular to an anti-aging plastic packaging material and a preparation method thereof. Background Art

[0002] Plastic packaging materials are widely used in the packaging of food, medicine, cosmetics, electronic products and other fields due to their light weight, high strength, easy molding, waterproof and moisture-proof properties. With the enhancement of environmental awareness, biodegradable plastic packaging materials have developed rapidly in recent years, among which biodegradable materials represented by polylactic acid (PLA) and polybutylene terephthalate-adipate (PBAT) have received extensive attention. However, traditional biodegradable plastic packaging materials are prone to aging problems during use, which are manifested in the decline of mechanical properties, yellowing of the surface, cracking and other phenomena, which seriously affect their service life and application scope.

[0003] The existing patent CN202411896240.4 proposes a biodegradable plastic particle and its preparation method and application. The biodegradable plastic particle includes the following components by weight: 50-80 parts of PLA, 20-50 parts of PBAT, 5-20 parts of filler, 1-8 parts of toughening agent, 1-5 parts of lubricant, and 5-10 parts of modifier; the modifier includes a polylactic acid-polyethylene glycol block copolymer and a polycaprolactone-polymethacrylate glycidyl ester block copolymer with a mass ratio of 1:19-19:1. Through the above technical solution, the problem of poor flexibility and strength of plastic particles in the related art is solved. However, this technology has obvious defects: on the one hand, it does not take into account the impact of environmental factors such as ultraviolet radiation and oxidation that the material faces during actual use, and lacks effective anti-aging functional components; on the other hand, its modification system is mainly aimed at improving mechanical properties and cannot effectively block ultraviolet radiation penetration and free radical diffusion, resulting in the material being prone to photooxidative degradation when used outdoors or in strong light environments. The service life is significantly shortened, which seriously limits the application scope and scenarios of this type of plastic packaging material. Summary of the invention

[0004] In view of this, the present invention proposes an anti-aging plastic packaging material and a preparation method thereof to solve the technical problems in the prior art that biodegradable plastic packaging materials have poor resistance to ultraviolet radiation and oxidation, short service life and limited applicable environment.

[0005] The technical solution of the present invention is achieved as follows: The present invention provides an anti-aging plastic packaging material, which comprises the following components by mass: 100-140 parts of polylactic acid, 60-80 parts of PBAT, 2-5 parts of a composite anti-aging agent, 1-2 parts of a lubricant, 2-4 parts of a flame retardant and 3-6 parts of a compatibilizer, wherein the composite anti-aging agent comprises a modified anti-aging agent obtained by compounding functionalized montmorillonite and modified silica, wherein the functionalized montmorillonite is a montmorillonite modified by grafting rare earth ions with carnosic acid, and the modified silica is a methyl epoxyoleate grafted silica.

[0006] The present invention compounds polylactic acid with PBAT and introduces a composite anti-aging agent system, wherein functionalized montmorillonite and modified silica work synergistically to form a multi-level protection mechanism, which not only effectively blocks ultraviolet radiation, but also captures and neutralizes free radicals, inhibits the diffusion of oxidative degradation chain reactions, and at the same time, the addition of a compatibilizer improves the interface bonding between the components, the lubricant improves the processing fluidity, and the flame retardant enhances the flame retardant properties of the material, so that the obtained plastic packaging material has excellent resistance to ultraviolet light, oxidation and heat aging, and has little effect on its degradable properties, significantly prolonging the service life and environmental adaptability of the material, and providing a new technical approach for the promotion and application of biodegradable plastic packaging materials.

[0007] On the basis of the above technical solution, preferably, the preparation method of the modified anti-aging agent comprises: S1, rare earth ion modified montmorillonite is dispersed in ethanol / water solution, diaminosilane coupling agent is added, stirred at room temperature for 1-2 hours, heated to 60-70°C and stirred for reaction for 3-4 hours to obtain silane modified montmorillonite; S2, dispersing the silane-modified montmorillonite in an ethanol / water solution, adding carnosic acid, and then adding 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide, stirring at room temperature for 0.5-1h, heating to 40-50°C and stirring for reaction for 7-8h to obtain functionalized montmorillonite; S3, dispersing nano-silica in an ethanol / water solution, adding an aminosilane coupling agent, heating to 70-80° C. and reacting for 4-6 hours to obtain amino-silica; S4, dispersing the amino silicon dioxide in anhydrous ethanol, adding methyl oleate and p-toluenesulfonic acid, heating to 60-70° C. and stirring for reaction for 4-6 hours to obtain modified silicon dioxide; S5. Disperse the modified silica and functionalized montmorillonite in ethanol, add glutaraldehyde aqueous solution, adjust the pH to 5.5-6.0, and react at 40-50° C. with stirring for 8-10 hours to obtain a modified anti-aging agent.

[0008] Specifically, in step S1, the abundant hydroxyl groups on the surface of montmorillonite modified by rare earth ions react with the methoxy groups of the bisaminosilane coupling agent to successfully introduce amino groups to the surface of montmorillonite. The problem of incompatibility between inorganic montmorillonite and organic matrix is ​​solved by silane modification. The surface of montmorillonite after silanization is changed from hydrophilic to organophilic, and the amino groups introduced on the surface provide active reaction sites for subsequent functionalization. At the same time, the formation of the silane layer protects the rare earth ions, preventing them from being lost during subsequent processing and use, and ensuring the durability of anti-aging performance. In step S2, the amino groups on the silane-modified montmorillonite react with the carboxyl groups of carnosic acid to graft carnosic acid with a polyphenol structure onto the surface of montmorillonite. The phenolic hydroxyl groups and conjugated double bond structures in the carnosic acid molecules can improve the antioxidant efficiency. At the same time, its aromatic structure also has ultraviolet absorption capacity, which can reduce the damage of ultraviolet rays to the material. In step S3, the surface activity of the aminated silica is enhanced, the affinity for organophilicity is improved, the agglomeration of silica nanoparticles in the polymer matrix is ​​effectively prevented, the interface compatibility is improved, and at the same time, the amino groups introduced on the surface provide reaction sites for the subsequent grafting of epoxy oleic acid methyl ester, laying the foundation for the construction of a multifunctional anti-aging system. In step S4, the amino groups on the surface of the aminated silica react with the epoxy groups in the epoxy oleic acid methyl ester molecules to graft the epoxy oleic acid methyl ester to the silica surface, and generate hydroxyl groups for subsequent cross-linking reactions. The ester groups in the epoxy oleic acid methyl ester molecules can effectively absorb and scatter ultraviolet radiation, reduce the direct attack of ultraviolet rays on the polymer main chain, and prevent the breakage of CC bonds during photodegradation; in addition, the long chain of the epoxy oleic acid methyl ester molecules can improve the toughness of the material, while being green and environmentally friendly.

[0009] In step S5, the amino groups remaining on the functionalized montmorillonite and the hydroxyl groups on the modified silica are covalently linked by glutaraldehyde as a cross-linking agent, thereby achieving a multi-component synergistic anti-aging effect: the layered montmorillonite and silica form a complementary physical barrier, significantly improving the oxygen barrier performance; the free radical capture ability of carnosic acid and the peroxide decomposition ability of rare earth ions work synergistically to comprehensively improve the antioxidant efficiency; the ultraviolet absorption ability of epoxy methyl oleate and the ultraviolet scattering ability of montmorillonite synergistically enhance the anti-ultraviolet light aging performance; in addition, the composite structure fixes each functional component on the nanocarrier to prevent its migration and volatilization during the processing process, thereby ensuring the durability and stability of the anti-aging effect.

[0010] On the basis of the above technical solution, preferably, in step S1, the preparation method of rare earth ion modified montmorillonite is as follows: Sodium montmorillonite, lanthanum nitrate and cerium nitrate are mixed in deionized water, ultrasonically dispersed, heated to 90-100° C. and stirred for reaction for 20-24 hours, centrifuged and dried to obtain rare earth ion modified montmorillonite, wherein the ratio of sodium montmorillonite, lanthanum nitrate and cerium nitrate is 1:(0.8-1.5):(0.8-1.5).

[0011] By using La in lanthanum nitrate and cerium nitrate in aqueous phase 3+ and Ce 3+ Na + Ion exchange reaction occurs. Since rare earth ions have higher charge density and stronger electrostatic force, they can be firmly bound to the interlayer position of montmorillonite, thus achieving stable loading of rare earth ions. This modification gives montmorillonite multiple anti-aging functions: on the one hand, La 3+ and Ce 3+ It has the characteristic of variable valence state and can catalyze the decomposition of peroxides produced during the aging process of polymers; on the other hand, rare earth ions can efficiently absorb and convert ultraviolet light energy, reducing the direct damage of ultraviolet radiation to polymers; in addition, the introduction of rare earth ions increases the interlayer spacing of montmorillonite, improves its compatibility and dispersibility with organic molecules, and strengthens the physical barrier effect of montmorillonite; finally, rare earth ions form a synergistic effect with the subsequently grafted carnosic acid, the former decomposing peroxides and the latter capturing free radicals, constructing a comprehensive antioxidant defense system.

[0012] On the basis of the above technical solution, preferably, in step S1, the mass ratio of the rare earth ion-modified montmorillonite to the bisaminosilane coupling agent is 100:3-7, and the bisaminosilane coupling agent is aminoethylaminopropylmethoxysilane coupling agent.

[0013] On the basis of the above technical scheme, preferably, in step S2, the mass ratio of silane-modified montmorillonite, carnosic acid, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide is 100:5-10:3-6:2-4.

[0014] On the basis of the above technical solution, preferably, in step S3, the mass ratio of nano-silica to aminosilane coupling agent is 100:5-8, and the aminosilane coupling agent is 3-aminopropyltriethoxysilane.

[0015] On the basis of the above technical solution, preferably, in step S4, the mass ratio of amino silica, methyl epoxyoleate and p-toluenesulfonic acid is 100:10-15:0.3-0.7.

[0016] On the basis of the above technical scheme, preferably, the composite antioxidant also includes a benzotriazole ultraviolet absorber, the mass ratio of the benzotriazole ultraviolet absorber to the modified antioxidant is 1:3-4, and the benzotriazole ultraviolet absorber is 2-(2-hydroxy-5-methylphenyl)benzotriazole or 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)benzotriazole.

[0017] There is an intramolecular hydrogen bond between the hydroxyl group and the triazole ring in the molecular structure of benzotriazole compounds, which can strongly and selectively absorb ultraviolet rays in the 290-400nm band. After absorbing energy, the energy is harmlessly converted and dissipated through the rapid tautomerism of the hydroxyl proton, forming an "excitation-conversion-dissipation" photostable cycle, which complements the modified anti-aging agent; specifically, in terms of ultraviolet protection, a triple mechanism of "absorption-scattering-conversion" is formed, in which benzotriazole molecules absorb ultraviolet rays, nanoparticles scatter ultraviolet rays, and rare earth ions convert ultraviolet energy, achieving full-band and high-efficiency The benzotriazole molecules are small and easy to migrate and volatilize. After being compounded with the modified antioxidant, they can be fixed on the surface or around the nanocarrier through intermolecular forces, significantly reducing their migration and loss during processing and use, and prolonging the anti-aging effect. Thirdly, there is a synergistic effect between the components in the composite system. The absorption of ultraviolet rays by benzotriazole reduces the antioxidant burden of carnosic acid, and the decomposition of peroxides by rare earth ions provides a more stable working environment for benzotriazole, together building a comprehensive protective barrier against multiple aging factors such as light, oxygen and heat.

[0018] On the basis of the above technical solution, preferably, the lubricant is calcium stearate or polyethylene wax, the flame retardant is triphenyl phosphate or tricresyl phosphate, and the compatibilizer is maleic anhydride grafted polylactic acid.

[0019] The present invention also provides a method for preparing an anti-aging plastic packaging material, comprising the following steps: S1. Place 85-90% of polylactic acid, PBAT, compatibilizer, lubricant and flame retardant in a drying oven, dry at 70-80° C. for 6-8 hours, and premix for 5-10 minutes to obtain a first mixture; S2, premixing the composite anti-aging agent with 10-15% of polylactic acid for 3-5 minutes to obtain a second mixture; S3, premixing the first mixed material and the second mixed material for 2-3 minutes, adding them into a twin-screw extruder, setting the temperature to 160-190° C. and the screw speed to 80-120 r / min, and performing melt blending to obtain a molten material; S4, extruding, granulating and blow-molding the molten material to obtain an anti-aging plastic packaging material.

[0020] The anti-aging plastic packaging material and the preparation method thereof of the present invention have the following beneficial effects compared with the prior art: (1) The anti-aging plastic packaging material provided by the present invention constructs a bioplastic material system with multiple protection mechanisms through the reasonable compounding of polylactic acid and PBAT, the introduction of a composite anti-aging agent, and the synergistic effect of a lubricant, a flame retardant, and a compatibilizer, thereby solving the technical problem that existing biodegradable plastics are prone to aging under ultraviolet light irradiation and an oxidative environment. The prepared plastic packaging material not only maintains good biodegradability, but also has excellent anti-ultraviolet and anti-oxidation properties.

[0021] (2) The modified antioxidant obtained by combining functionalized montmorillonite and modified silica in the present invention forms a complementary physical barrier. The phenolic hydroxyl group of carnosic acid efficiently captures free radicals, the rare earth ions catalyze the decomposition of peroxides, the nanoparticles shield ultraviolet rays and oxygen penetration, and the unsaturated bonds and ester groups in the epoxy oleic acid methyl ester molecules can effectively absorb ultraviolet energy and convert it into heat energy. The synergistic effect of the three blocks the propagation of the photooxidative aging chain reaction. At the same time, the fixing effect of the nanocarrier prevents the migration and loss of the anti-aging functional groups, ensuring the durability of the anti-aging effect.

[0022] (3) The combination of benzotriazole UV absorbers and modified antioxidants constructs a "selective absorption-scattering-conversion" multiple protection system. Benzotriazole compounds selectively absorb ultraviolet rays and convert them harmlessly through the intramolecular hydrogen bond transfer mechanism, which complements the scattering effect of nanoparticles and the energy conversion effect of rare earth ions, significantly enhancing the material's anti-ultraviolet aging performance; benzotriazole's absorption of ultraviolet rays reduces the antioxidant burden of carnosic acid, while the decomposition of peroxides by rare earth ions provides benzotriazole with a more stable working environment, together building a comprehensive protection barrier against multiple aging factors such as light, oxygen and heat. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Aminoethylaminopropylmethoxysilane coupling agent was purchased from Yisheng New Materials Co., Ltd., model OFS-6020; polylactic acid was purchased from Shanghai Yuanye Biotechnology Co., Ltd., with a molecular weight of 3000-15000; PBAT was purchased from Dongguan Shunying Plastic Raw Materials Co., Ltd., model F2224; triphenyl phosphate was purchased from Hubei Keward Chemical Co., Ltd.; maleic anhydride grafted polylactic acid was purchased from Xi'an Qiyue Biotechnology Co., Ltd.

[0025] Example 1

[0026] The present embodiment provides an anti-aging plastic packaging material, comprising the following components: 120 parts of polylactic acid, 70 parts of PBAT, 3.5 parts of a composite anti-aging agent, 1.5 parts of calcium stearate, 3 parts of triphenyl phosphate, and 4.5 parts of maleic anhydride grafted polylactic acid, wherein the composite anti-aging agent is composed of 2-(2-hydroxy-5-methylphenyl)benzotriazole and a modified anti-aging agent in a mass ratio of 1:3.5, wherein the preparation method of the modified anti-aging agent is as follows: (1) Disperse 100 g of sodium montmorillonite in 2 L of deionized water, ultrasonically disperse for 12 min, then add 115 g of lanthanum nitrate and 115 g of cerium nitrate, continue ultrasonically disperse for 12 min, heat to 95 ° C and stir to react for 22 h, cool to room temperature, centrifuge, wash with deionized water three times to remove unexchanged nitrate, vacuum dry, grind through a 200 mesh sieve, and obtain rare earth ion modified montmorillonite; (2) 100 g of rare earth ion-modified montmorillonite was dispersed in 1 L of ethanol / water solution (volume ratio of 7:3), 5 g of aminoethylaminopropylmethoxysilane coupling agent (pre-dissolved in 50 ml of ethanol) was added, and the mixture was stirred at room temperature for 1.5 h, heated to 65 °C and stirred for 3-4 h, cooled to room temperature, centrifuged, washed twice with ethanol and deionized water, and dried in vacuo to obtain silane-modified montmorillonite; (3) Disperse 100 g of silane-modified montmorillonite in 800 ml of ethanol / water solution (volume ratio of 4:1), perform ultrasonic dispersion, add 8 g of carnosic acid, stir for 15 min, then add 4.5 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 3 g of N-hydroxysuccinimide, stir at room temperature for 0.8 h, adjust the pH to 6.5-7.0, heat to 45 °C and stir for 7.5 h, cool to room temperature, centrifuge, wash with DMF, ethanol and deionized water twice each, and dry in vacuo to obtain functionalized montmorillonite; (4) Disperse 100 g of nano-silica in 1 L of ethanol / water solution (volume ratio of 4:1), perform ultrasonic dispersion, add 6.5 g of 3-aminopropyltriethoxysilane, heat to 75 °C for 5 h, cool to room temperature, centrifuge, wash with ethanol and deionized water three times each, and vacuum dry to obtain amino-silica; (5) Disperse 100 g of amino-modified silica in 800 ml of anhydrous ethanol, disperse by ultrasonication, add 13 g of methyl oleate, stir for 15 min, then add 0.5 g of p-toluenesulfonic acid, heat to 65 °C and stir for 5 h, cool to room temperature, centrifuge, wash with anhydrous ethanol 4 times to remove unreacted reagents, and vacuum dry to obtain modified silica; (6) Disperse 60 g of modified silica and 40 g of functionalized montmorillonite in 1 L of ethanol, perform ultrasonic dispersion, add 50 ml of 25% glutaraldehyde aqueous solution, stir for 15 min, adjust the pH to 5.8 with dilute hydrochloric acid (0.1 mol / L), heat to 45 °C and stir for 9 h, cool to room temperature, centrifuge, wash with ethanol and deionized water three times each, vacuum dry, and grind through a 200-mesh sieve to obtain a modified antioxidant.

[0027] The preparation method of the anti-aging plastic packaging material is as follows: 105 parts of polylactic acid, 70 parts of PBAT, 4 parts of maleic anhydride grafted polyethylene, 1.5 parts of calcium stearate and 3 parts of ammonium polyphosphate are placed in a drying oven, dried at 75°C for 7 hours, and premixed for 8 minutes to obtain a first mixture; 3 parts of a composite anti-aging agent are premixed with 15 parts of polylactic acid for 4 minutes to obtain a second mixture; the first mixture and the second mixture are premixed for 2.5 minutes, added into a twin-screw extruder, the temperature is set to 160-190°C, the screw speed is 100r / min, and melt blending is performed to obtain a molten material; the molten material is extruded, granulated and blow-molded to obtain an anti-aging plastic packaging material.

[0028] Example 2

[0029] This embodiment provides an anti-aging plastic packaging material, comprising the following components: 100 parts of polylactic acid, 60 parts of PBAT, 2 parts of a composite anti-aging agent, 1 part of polyethylene wax, 2 parts of tricresyl phosphate, and 3 parts of maleic anhydride grafted polylactic acid, wherein the composite anti-aging agent is composed of 2-(2-hydroxy-5-methylphenyl)benzotriazole and a modified anti-aging agent in a mass ratio of 1:3, wherein the preparation method of the modified anti-aging agent is as follows: (1) Disperse 100 g of sodium montmorillonite in 2 L of deionized water, perform ultrasonic dispersion for 10 min, then add 80 g of lanthanum nitrate and 80 g of cerium nitrate, continue ultrasonic dispersion for 10 min, heat to 90 ° C and stir to react for 24 h, cool to room temperature, centrifuge, wash with deionized water three times to remove unexchanged nitrate, vacuum dry, grind through a 200 mesh sieve, and obtain rare earth ion modified montmorillonite; (2) 100 g of rare earth ion-modified montmorillonite was dispersed in 1 L of ethanol / water solution (volume ratio of 7:3), 3 g of aminoethylaminopropylmethoxysilane coupling agent (pre-dissolved in 30 ml of ethanol) was added, and the mixture was stirred at room temperature for 1 h, heated to 60 °C for reaction for 4 h, cooled to room temperature, centrifuged, washed twice with ethanol and deionized water respectively, and vacuum dried to obtain silane-modified montmorillonite; (3) Disperse 100 g of silane-modified montmorillonite in 800 ml of ethanol / water solution (volume ratio of 4:1), perform ultrasonic dispersion, add 5 g of carnosic acid, stir for 15 min, then add 3 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 2 g of N-hydroxysuccinimide, stir at room temperature for 0.5 h, adjust the pH to 6.5-7.0, heat to 40 °C and stir for 8 h, cool to room temperature, centrifuge, wash twice with DMF, ethanol and deionized water respectively, and vacuum dry to obtain functionalized montmorillonite; (4) Disperse 100 g of nano-silica in 1 L of ethanol / water solution (volume ratio of 4:1), perform ultrasonic dispersion, add 5 g of 3-aminopropyltriethoxysilane, heat to 70 °C for 6 h, cool to room temperature, centrifuge, wash with ethanol and deionized water three times each, and vacuum dry to obtain amino-silica; (5) Disperse 100 g of amino-modified silica in 800 ml of anhydrous ethanol, perform ultrasonic dispersion, add 10 g of methyl oleate, stir for 15 min, then add 0.3 g of p-toluenesulfonic acid, heat to 60 °C and stir for 6 h, cool to room temperature, centrifuge, wash with anhydrous ethanol 4 times to remove unreacted reagents, and vacuum dry to obtain modified silica; (6) Disperse 55 g of modified silica and 35 g of functionalized montmorillonite in 1 L of ethanol, perform ultrasonic dispersion, add 45 ml of 25% glutaraldehyde aqueous solution, stir for 15 min, adjust the pH to 5.8 with dilute hydrochloric acid (0.1 mol / L), heat to 40 °C and stir for 10 h, cool to room temperature, centrifuge, wash with ethanol and deionized water three times each, vacuum dry, and grind through a 200-mesh sieve to obtain a modified antioxidant.

[0030] The preparation method of the anti-aging plastic packaging material is as follows: 90 parts of polylactic acid, 60 parts of PBAT, 3 parts of maleic anhydride grafted polylactic acid, 1 part of polyethylene wax and 2 parts of tricresyl phosphate are placed in a drying oven, dried at 70°C for 8 hours, and premixed for 5 minutes to obtain a first mixture; 2 parts of a composite anti-aging agent are premixed with 10 parts of polylactic acid for 3 minutes to obtain a second mixture; the first mixture and the second mixture are premixed for 2 minutes, added into a twin-screw extruder, the temperature is set to 160-190°C, the screw speed is 80r / min, and melt blending is performed to obtain a molten material; the molten material is extruded, granulated and blow-molded to obtain an anti-aging plastic packaging material.

[0031] Example 3

[0032] This embodiment provides an anti-aging plastic packaging material, comprising the following components: 140 parts of polylactic acid, 80 parts of PBAT, 5 parts of a composite anti-aging agent, 2 parts of calcium stearate, 4 parts of triphenyl phosphate, and 6 parts of maleic anhydride grafted polylactic acid, wherein the composite anti-aging agent is composed of 2-(2-hydroxy-5-methylphenyl)benzotriazole and a modified anti-aging agent in a mass ratio of 1:4, wherein the preparation method of the modified anti-aging agent is as follows: (1) Disperse 100 g of sodium montmorillonite in 2 L of deionized water, ultrasonically disperse for 15 min, then add 150 g of lanthanum nitrate and 150 g of cerium nitrate, continue ultrasonically disperse for 15 min, heat to 100 °C and stir to react for 20 h, cool to room temperature, centrifuge, wash with deionized water three times to remove unexchanged nitrate, vacuum dry, and grind through a 200 mesh sieve to obtain rare earth ion modified montmorillonite; (2) 100 g of rare earth ion-modified montmorillonite was dispersed in 1 L of ethanol / water solution (volume ratio of 7:3), 7 g of aminoethylaminopropylmethoxysilane coupling agent (pre-dissolved in 70 ml of ethanol) was added, and the mixture was stirred at room temperature for 2 h. The mixture was heated to 70 °C and stirred for 3 h. The mixture was cooled to room temperature, centrifuged, washed twice with ethanol and deionized water, and dried in vacuo to obtain silane-modified montmorillonite. (3) Disperse 100 g of silane-modified montmorillonite in 800 ml of ethanol / water solution (volume ratio of 4:1), perform ultrasonic dispersion, add 10 g of carnosic acid, stir for 15 min, then add 6 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 4 g of N-hydroxysuccinimide, stir at room temperature for 1 h, adjust the pH to 6.5-7.0, heat to 50 °C and stir for 7 h, cool to room temperature, centrifuge, wash with DMF, ethanol and deionized water twice each, and vacuum dry to obtain functionalized montmorillonite; (4) Disperse 100 g of nano-silica in 1 L of ethanol / water solution (volume ratio of 4:1), perform ultrasonic dispersion, add 8 g of 3-aminopropyltriethoxysilane, heat to 80 °C for 4 h, cool to room temperature, centrifuge, wash with ethanol and deionized water three times each, and vacuum dry to obtain amino-silica; (5) Disperse 100 g of amino-modified silica in 800 ml of anhydrous ethanol, disperse by ultrasonication, add 15 g of methyl oleate, stir for 15 min, then add 0.7 g of p-toluenesulfonic acid, heat to 70 °C and stir for 4 h, cool to room temperature, centrifuge, wash with anhydrous ethanol 4 times to remove unreacted reagents, and vacuum dry to obtain modified silica; (6) Disperse 65 g of modified silica and 45 g of functionalized montmorillonite in 1 L of ethanol, perform ultrasonic dispersion, add 50 ml of 25% glutaraldehyde aqueous solution, stir for 15 min, adjust the pH to 5.8 with dilute hydrochloric acid (0.1 mol / L), heat to 50 °C and stir for 8 h, cool to room temperature, centrifuge, wash with ethanol and deionized water three times each, vacuum dry, and grind through a 200-mesh sieve to obtain a modified antioxidant.

[0033] The preparation method of the anti-aging plastic packaging material is as follows: 119 parts of polylactic acid, 80 parts of PBAT, 6 parts of maleic anhydride grafted polylactic acid, 2 parts of calcium stearate and 4 parts of triphenyl phosphate were placed in a drying oven, dried at 80°C for 6 hours, and premixed for 10 minutes to obtain a first mixture; 5 parts of a composite anti-aging agent were premixed with 21 parts of polylactic acid for 5 minutes to obtain a second mixture; the first mixture and the second mixture were premixed for 3 minutes, added into a twin-screw extruder, the temperature was set to 160-190°C, the screw speed was set to 120r / min, and melt blending was performed to obtain a molten material; the molten material was extruded, granulated and blow-molded to obtain an anti-aging plastic packaging material.

[0034] Comparative Example 1 This comparative example provides an anti-aging plastic packaging material, comprising the following components: 120 parts of polylactic acid, 70 parts of PBAT, 3.5 parts of a composite anti-aging agent, 1.5 parts of calcium stearate, 3 parts of triphenyl phosphate and 4.5 parts of maleic anhydride grafted polylactic acid, wherein the composite anti-aging agent is a modified anti-aging agent, wherein the preparation method of the modified anti-aging agent is the same as that of Example 1.

[0035] Comparative Example 2 This comparative example provides an anti-aging plastic packaging material, comprising the following components: 120 parts of polylactic acid, 70 parts of PBAT, 3.5 parts of a composite anti-aging agent, 1.5 parts of calcium stearate, 3 parts of triphenyl phosphate and 4.5 parts of maleic anhydride grafted polylactic acid, wherein the composite anti-aging agent is composed of 2-(2-hydroxy-5-methylphenyl)benzotriazole and a modified anti-aging agent in a mass ratio of 1:3.5, wherein the preparation method of the modified anti-aging agent is different from that of Example 1 in that the montmorillonite is not modified with rare earth ions, namely: (1) 100 g of sodium montmorillonite was dispersed in 1 L of ethanol / water solution (volume ratio of 7:3), 5 g of aminoethylaminopropylmethoxysilane coupling agent (pre-dissolved in 50 ml of ethanol) was added, and the mixture was stirred at room temperature for 1.5 h, heated to 65 ° C, stirred for 3-4 h, cooled to room temperature, centrifuged, washed twice with ethanol and deionized water, and vacuum dried to obtain silane-modified montmorillonite. The subsequent steps were the same as those in Example 1.

[0036] Comparative Example 3 This comparative example provides an anti-aging plastic packaging material, comprising the following components: 120 parts of polylactic acid, 70 parts of PBAT, 3.5 parts of a composite anti-aging agent, 1.5 parts of calcium stearate, 3 parts of triphenyl phosphate and 4.5 parts of maleic anhydride grafted polylactic acid, wherein the composite anti-aging agent is composed of 2-(2-hydroxy-5-methylphenyl)benzotriazole and a modified anti-aging agent in a mass ratio of 1:3.5, wherein the preparation method of the modified anti-aging agent is different from that of Example 1 in that montmorillonite is not grafted with carnosic acid, namely: (1) Disperse 100 g of sodium montmorillonite in 2 L of deionized water, ultrasonically disperse for 12 min, then add 115 g of lanthanum nitrate and 115 g of cerium nitrate, continue ultrasonically disperse for 12 min, heat to 95 ° C and stir to react for 22 h, cool to room temperature, centrifuge, wash with deionized water three times to remove unexchanged nitrate, vacuum dry, grind through a 200 mesh sieve, and obtain rare earth ion modified montmorillonite; (2) 100 g of rare earth ion-modified montmorillonite was dispersed in 1 L of ethanol / water solution (volume ratio of 7:3), 5 g of aminoethylaminopropylmethoxysilane coupling agent (pre-dissolved in 50 ml of ethanol) was added, and the mixture was stirred at room temperature for 1.5 h, heated to 65 °C and stirred for 3-4 h, cooled to room temperature, centrifuged, washed twice with ethanol and deionized water, and dried in vacuo to obtain silane-modified montmorillonite; (3) Disperse 100 g of nano-silica in 1 L of ethanol / water solution (volume ratio of 4:1), perform ultrasonic dispersion, add 6.5 g of 3-aminopropyltriethoxysilane, heat to 75 °C for 5 h, cool to room temperature, centrifuge, wash with ethanol and deionized water three times each, and vacuum dry to obtain amino-silica; (4) Disperse 100 g of amino-modified silica in 800 ml of anhydrous ethanol, perform ultrasonic dispersion, add 13 g of methyl epoxyoleate, stir for 15 min, then add 0.5 g of p-toluenesulfonic acid, heat to 65 °C and stir for 5 h, cool to room temperature, centrifuge, wash with anhydrous ethanol 4 times to remove unreacted reagents, and vacuum dry to obtain modified silica; (5) Disperse 60 g of modified silica and 40 g of silane-modified montmorillonite in 1 L of ethanol, perform ultrasonic dispersion, add 50 ml of 25% glutaraldehyde aqueous solution, stir for 15 min, adjust the pH to 5.8 with dilute hydrochloric acid (0.1 mol / L), heat to 45 °C and stir for 9 h, cool to room temperature, centrifuge, wash with ethanol and deionized water three times each, vacuum dry, and grind through a 200-mesh sieve to obtain a modified antioxidant.

[0037] Comparative Example 4 This comparative example provides an anti-aging plastic packaging material, comprising the following components: 120 parts of polylactic acid, 70 parts of PBAT, 3.5 parts of a composite anti-aging agent, 1.5 parts of calcium stearate, 3 parts of triphenyl phosphate and 4.5 parts of maleic anhydride grafted polylactic acid, wherein the composite anti-aging agent is composed of 2-(2-hydroxy-5-methylphenyl)benzotriazole and a modified anti-aging agent in a mass ratio of 1:3.5, wherein the preparation method of the modified anti-aging agent is different from that of Example 1 in that the silicon dioxide is not grafted with epoxy oleic acid methyl ester, namely: Steps (1) to (4) are the same as in Example 1; (5) Disperse 60 g of amino silica and 40 g of functionalized montmorillonite in 1 L of ethanol, perform ultrasonic dispersion, add 50 ml of 25% glutaraldehyde aqueous solution, stir for 15 min, adjust the pH to 5.8 with dilute hydrochloric acid (0.1 mol / L), heat to 45 °C and stir for 9 h, cool to room temperature, centrifuge, wash with ethanol and deionized water three times each, vacuum dry, and grind through a 200-mesh sieve to obtain a modified antioxidant.

[0038] Comparative Example 5 This comparative example provides an anti-aging plastic packaging material, comprising the following components: 120 parts of polylactic acid, 70 parts of PBAT, 3.5 parts of a composite anti-aging agent, 1.5 parts of calcium stearate, 3 parts of triphenyl phosphate and 4.5 parts of maleic anhydride grafted polylactic acid, wherein the composite anti-aging agent is composed of 2-(2-hydroxy-5-methylphenyl)benzotriazole and a modified anti-aging agent in a mass ratio of 1:3.5, wherein the preparation method of the modified anti-aging agent is different from that of Example 1 in that the modified silica and the functionalized montmorillonite are not cross-linked, that is: Steps (1) to (5) are the same as in Example 1; (6) Disperse 60 g of modified silica and 40 g of functionalized montmorillonite in 1 L of ethanol, perform ultrasonic dispersion, add 50 ml of aqueous solution, stir for 15 min, heat to 45 °C and stir for 9 h, cool to room temperature, centrifuge, wash with ethanol and deionized water three times each, vacuum dry, and grind through a 200-mesh sieve to obtain a modified antioxidant.

[0039] Performance Testing After the anti-aging plastic packaging materials prepared in the examples and comparative examples were prepared into standard samples, performance tests were carried out, including tensile strength, elongation at break, heat deformation temperature and aging performance tests, wherein tensile strength and elongation at break were tested according to "GB / T1040.3-2006 Determination of tensile properties of plastics Part 3: Test conditions for films and sheets"; after hot pressing into sheets, heat deformation temperature was tested according to relevant requirements in GB / T1634 national standard; aging test: the sample was placed in a xenon lamp aging box at 80°C for 1200 hours, and the tensile strength change rate = (tensile strength after ultraviolet aging treatment / original tensile strength of the sample) × 100%. The test results are shown in Table 1.

[0040] Table 1

[0041] As shown in Table 1, the technical solution of the present invention significantly improves the mechanical properties and anti-aging properties of the material through the synergistic effect of benzotriazole and modified anti-aging agent (including rare earth modified montmorillonite, carnosic acid grafting, epoxy oleic acid methyl ester modified silica and cross-linked structure). Benzotriazole delays light aging by absorbing ultraviolet rays, rare earth modified montmorillonite enhances filler dispersibility and thermal stability, carnosic acid scavenges free radicals to inhibit oxidative degradation, epoxy oleic acid methyl ester improves interfacial compatibility, and the cross-linked network strengthens the combination of filler and matrix.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An anti-aging plastic packaging material, characterized in that: The invention comprises the following components by weight: 100-140 parts of polylactic acid, 60-80 parts of PBAT, 2-5 parts of composite anti-aging agent, 1-2 parts of lubricant, 2-4 parts of flame retardant and 3-6 parts of compatibilizer. The composite anti-aging agent comprises a modified anti-aging agent obtained by compounding functionalized montmorillonite and modified silica. The functionalized montmorillonite is montmorillonite modified by grafting rare earth ions with carnosic acid, and the modified silica is silica grafted with methyl oleate epoxy.

2. The anti-aging plastic packaging material according to claim 1, characterized in that: The preparation method of the modified anti-aging agent comprises: S1, rare earth ion modified montmorillonite is dispersed in ethanol / water solution, diaminosilane coupling agent is added, stirred at room temperature for 1-2 hours, heated to 60-70°C and stirred for reaction for 3-4 hours to obtain silane modified montmorillonite; S2, dispersing the silane-modified montmorillonite in an ethanol / water solution, adding carnosic acid, and then adding 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide, stirring at room temperature for 0.5-1h, heating to 40-50°C and stirring for reaction for 7-8h to obtain functionalized montmorillonite; S3, dispersing nano-silica in an ethanol / water solution, adding an aminosilane coupling agent, heating to 70-80° C. and reacting for 4-6 hours to obtain amino-silica; S4, dispersing the amino silicon dioxide in anhydrous ethanol, adding methyl oleate and p-toluenesulfonic acid, heating to 60-70° C. and stirring for reaction for 4-6 hours to obtain modified silicon dioxide; S5. Disperse the modified silica and functionalized montmorillonite in ethanol, add glutaraldehyde aqueous solution, adjust the pH to 5.5-6.0, and react at 40-50° C. with stirring for 8-10 hours to obtain a modified anti-aging agent.

3. The anti-aging plastic packaging material according to claim 2, characterized in that: In step S1, the preparation method of rare earth ion modified montmorillonite is as follows: Sodium montmorillonite, lanthanum nitrate and cerium nitrate are mixed in deionized water, ultrasonically dispersed, heated to 90-100° C. and stirred for reaction for 20-24 hours, centrifuged and dried to obtain rare earth ion modified montmorillonite, wherein the ratio of sodium montmorillonite, lanthanum nitrate and cerium nitrate is 1:(0.8-1.5):(0.8-1.5).

4. The anti-aging plastic packaging material according to claim 2, characterized in that: In step S1, the mass ratio of the rare earth ion modified montmorillonite to the bisaminosilane coupling agent is 100:3-7, and the bisaminosilane coupling agent is aminoethylaminopropylmethoxysilane coupling agent.

5. The anti-aging plastic packaging material according to claim 2, characterized in that: In step S2, the mass ratio of silane-modified montmorillonite, carnosic acid, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide is 100:5-10:3-6:2-4.

6. The anti-aging plastic packaging material according to claim 2, characterized in that: In step S3, the mass ratio of nano-silica to aminosilane coupling agent is 100:5-8, and the aminosilane coupling agent is 3-aminopropyltriethoxysilane.

7. The anti-aging plastic packaging material according to claim 2, characterized in that: In step S4, the mass ratio of amino silica, epoxy methyl oleate and p-toluenesulfonic acid is 100:10-15:0.3-0.

7.

8. The anti-aging plastic packaging material according to claim 1, characterized in that: The composite anti-aging agent also includes a benzotriazole ultraviolet absorber, the mass ratio of the benzotriazole ultraviolet absorber to the modified anti-aging agent is 1:3-4, and the benzotriazole ultraviolet absorber is 2-(2-hydroxy-5-methylphenyl)benzotriazole or 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)benzotriazole.

9. The anti-aging plastic packaging material according to claim 1, characterized in that: The lubricant is calcium stearate or polyethylene wax, the flame retardant is triphenyl phosphate or tricresyl phosphate, and the compatibilizer is maleic anhydride grafted polylactic acid.

10. A method for preparing an anti-aging plastic packaging material according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) placing 85-90% of polylactic acid, PBAT, compatibilizer, lubricant and flame retardant in a drying oven, drying at 70-80° C. for 6-8 hours, and premixing for 5-10 minutes to obtain a first mixed material; (2) premixing the composite anti-aging agent with 10-15% polylactic acid for 3-5 minutes to obtain a second mixture; (3) premixing the first mixed material and the second mixed material for 2-3 minutes, adding them into a twin-screw extruder, setting the temperature to 160-190°C and the screw speed to 80-120 r / min, and performing melt blending to obtain a molten material; (4) The molten material is extruded, granulated and blow-molded to obtain an anti-aging plastic packaging material.

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